Preserving Arran’s Coastline

Preserving Arran’s Coastline

Scotland | NAUE GmbH & Co. KG

The picturesque shore on the Isle of Arran in the Firth of Clyde (just off the west coast of Scotland) was threatened by erosion caused by constant wave attack. The erosion even unearthed a restored landfill, which heightened the concern with the stability and environmental soundness of the beachfront. The landfill in question was closed around 1950 and restored with topsoil and marram grass (a simple, common approach in the time before geosynthetic caps).

When this site was exposed by shoreline wave erosion, a rectification project was undertaken by North Ayrshire Council’s Infrastructure and Design Service. This included the selection of two geosynthetic solutions: Soft Rock Type E (R601) sand containers and Terrafix® 609 geotextile for filtration, erosion control and scour protection.

NAUE’s sand containers arrived on site in an unfilled state. This minimized transportation costs and allowed the project to utilize locally sourced fill.

The sand containers have a floor area of about 3.5sqm and each container is able to carry a mass of up to 2 tonnes. When sealed, the pillow-shaped sand containers measure about 300mm thick.

Material was excavated to show the front row of sand containers to be placed to a depth of about 1m below the surface of the beach. NAUE’s Terrafix® 609 was installed as a filter/separator between the sand containers and the loose material to ensure material stayed in place to provide the protection from the coastal erosion. Able to trap sand in its pore spaces, Terrafix® 609 was designed here to replicate the buffeting effects of sand without the sand being removed. The excavated material was then backfilled into a buffer zone between the shoreline and the old landfill.

Scotland | NAUE GmbH & Co. KG

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Once all of the sand containers had been placed in position, they were covered with more sand – a planning requirement which met the concerns of the local residents about the appearance of the finished job. Most importantly, the work has overcome the problem of 70-year-old rubbish finding its way onto the coastline.

Today, Brodick’s coastline is safer and more durable, and its aesthetic character has been preserved.